I recently abandoned the US for Canada. I had been living in the US illegally for 15 years (since the age of 11). I got an opportunity to conduct biological research at the University of Alberta, AB, and Canada. I'm fully funded to live in Canada by the institution. Anyway, I would like to return to the US in 2013 for my 10 year high school reunion. I would like to know how likely I would be to get a tourist visa given my recent history. I have no intentions of staying in the US, just visiting. Am I automatically banned?
Look into a 212(d)(3) waiver, which should allow you an entry. Ask CBP at the border how much time they need to process the waiver (usually a few weeks).